bombproof

Short definition from Wiktionary

Adjective

1. 1
   Sufficiently strong to resist the effects of a blast from a bomb.
2. 2
   Very sturdy; as if built to resist the effects of a blast from a bomb.

Noun

1. 1
   An air-raid shelter, a structure designed to give protection against air raids and bombs.

Verb

1. 1
   To make resistant to bomb blasts.